#include <ctype.h>

#define ALRMMASK (1<<(SIGALRM-1))
#define KILLMASK (1<<(SIGKILL-1))
#define INTMASK (1<<(SIGINT-1))
#define QUITMASK (1<<(SIGQUIT-1))
#define TSTPMASK (1<<(SIGTSTP-1))

#include <linux/sched.h>
#include <linux/tty.h>
#include <asm/segment.h>
#include <asm/system.h>

#define _L_FLAG(tty,f)  ((tty)->termios.c_lflag & f)
#define _I_FLAG(tty,f)  ((tty)->termios.c_iflag & f)
#define _O_FLAG(tty,f)  ((tty)->termios.c_oflag & f)

#define L_CANON(tty)    _L_FLAG((tty),ICANON)
#define L_ISIG(tty)     _L_FLAG((tty),ISIG)
#define L_ECHO(tty)     _L_FLAG((tty),ECHO)
#define L_ECHOE(tty)    _L_FLAG((tty),ECHOE)
#define L_ECHOK(tty)    _L_FLAG((tty),ECHOK)
#define L_ECHOCTL(tty)  _L_FLAG((tty),ECHOCTL)
#define L_ECHOKE(tty)   _L_FLAG((tty),ECHOKE)

#define I_UCLC(tty) _I_FLAG((tty),IUCLC)
#define I_NLCR(tty) _I_FLAG((tty),INLCR)
#define I_CRNL(tty) _I_FLAG((tty),ICRNL)
#define I_NOCR(tty) _I_FLAG((tty),IGNCR)

#define O_POST(tty) _O_FLAG((tty),OPOST)
#define O_NLCR(tty) _O_FLAG((tty),ONLCR)
#define O_CRNL(tty) _O_FLAG((tty),OCRNL)
#define O_NLRET(tty)    _O_FLAG((tty),ONLRET)
#define O_LCUC(tty) _O_FLAG((tty),OLCUC)

struct tty_struct tty_table[] = {
    {
        {ICRNL,         // 将输入的CR转换为NL
        OPOST | ONLCR,  // 将输出的NL转换为CRNL
        0,              // 控制模式初始化为0
        ISIG | ICANON | ECHO | ECHOCTL | ECHOKE,    // 本地模式标志
        0,
        INIT_C_CC},     // 控制字符数组
        0,
        0,
        con_write,
        {0, 0, 0, 0, ""},
        {0, 0, 0, 0, ""},
        {0, 0, 0, 0, ""}
    }
};

struct tty_queue *table_list[] = {
    &tty_table[0].read_q, &tty_table[0].write_q,
};

void tty_init(void)
{
    con_init();
}

void tty_intr(struct tty_struct *tty, int mask)
{
    int i;

    if (tty->pgrp <= 0)
        return;
    for (i = 0; i < NR_TASKS; i++)
        if (task[i] && task[i]->pgrp == tty->pgrp)
            task[i]->signal |= mask;
}

static void sleep_if_empty(struct tty_queue *queue)
{
    cli();
    while (!current->signal && EMPTY(*queue))
        interruptible_sleep_on(&queue->proc_list);
    sti();
}

void wait_for_keypress(void)
{
    sleep_if_empty(&tty_table[0].secondary);
}

void copy_to_cooked(struct tty_struct *tty)
{
    signed char c;
    while (!EMPTY(tty->read_q) && !FULL(tty->secondary)) {
        GETCH(tty->read_q, c);
        if (c == 13)
            if (I_CRNL(tty))
                c = 10;
            else if (I_NOCR(tty))
                continue;
            else ;
        else if (c == 10 && I_NLCR(tty))
            c = 13;
        if (I_UCLC(tty))    // 所有字母都转换为小写
            c = tolower(c);
        if (L_CANON(tty)) { // 使用标准输入模式
            if (c == KILL_CHAR(tty)) {  // ^U 删除当前行的字符
                while(!(EMPTY(tty->secondary) ||
                        (c = LAST(tty->secondary)) == 10 ||
                        c == EOF_CHAR(tty))) {  // \0
                    if (L_ECHO(tty)) {
                        if (c < 32)
                            PUTCH(127, tty->write_q);
                        PUTCH(127, tty->write_q);
                        tty->write(tty);
                    }
                    DEC(tty->secondary.head);
                }
                continue;
            }
            if (c == ERASE_CHAR(tty)) { // del 删除一个字符
                if (EMPTY(tty->secondary) ||
                    (c = LAST(tty->secondary)) == 10 ||
                    c == EOF_CHAR(tty))
                    continue;
                if (L_ECHO(tty)) {
                    if (c < 32)
                        PUTCH(127, tty->write_q);
                    PUTCH(127, tty->write_q);
                    tty->write(tty);
                }
                DEC(tty->secondary.head);
                continue;
            }
            if (c == STOP_CHAR(tty)) {  // ^S 停止终端
                tty->stopped = 1;
                continue;
            }
            if (c == START_CHAR(tty)) { // ^Q 启动终端
                tty->stopped = 0;
                continue;
            }
        }
        if (L_ISIG(tty)) {
            if (c == INTR_CHAR(tty)) {  // ^C
                tty_intr(tty, INTMASK);
                continue;
            }
            if (c == QUIT_CHAR(tty)) {  // ^I
                tty_intr(tty, QUITMASK);
                continue;
            }
        }
        if (c == 10 || c == EOF_CHAR(tty))
            tty->secondary.data++;
        if (L_ECHO(tty)) {
            if (c == 10) {
                PUTCH(10, tty->write_q);
                PUTCH(13, tty->write_q);
            } else if (c < 32) {
                if (L_ECHOCTL(tty)) {
                    PUTCH('^', tty->write_q);
                    PUTCH(c + 64, tty->write_q);
                }
            } else
                PUTCH(c, tty->write_q);
            tty->write(tty);
        }
        PUTCH(c, tty->secondary);
    }
    wake_up(&tty->secondary.proc_list);
}

int tty_write(unsigned channel, char *buf, int nr)
{
    static int cr_flag = 0;
    struct tty_struct *tty;
    char c, *b = buf;

    if (channel > 0 || nr < 0)
        return -1;
    tty = channel + tty_table;

    while (nr > 0) {
        if (current->signal)
            break;
        while (nr > 0 && !FULL(tty->write_q)) {
            c = get_fs_byte(b);
            if (O_POST(tty)) {
                if (c == '\r' && O_CRNL(tty))
                    c = '\n';
                else if (c=='\n' && O_NLRET(tty))
                    c = '\r';
                if (c == '\n' && !cr_flag && O_NLCR(tty)) {
                    cr_flag = 1;
                    PUTCH(13, tty->write_q);
                    continue;
                }
                if (O_LCUC(tty))
                    c = toupper(c);
            }
            b++; nr--;
            PUTCH(c, tty->write_q);
        }
        tty->write(tty);
        if (nr > 0)
            schedule();
    }
    return (b - buf);
}

void do_tty_interrupt(int tty)
{
    copy_to_cooked(tty_table + tty);
}
